With his brother Lorenzo Niles Fowler, he opened a phrenological office in New York City. Orson wrote and lectured on phrenology, preservation of health, popular education and social reform from 1834 to 1887. Lorenzo and his wife Lydia Folger Fowler lectured frequently with Orson on the subject of phrenology.[1] The three were "in large measure" responsible for the mid-19th century popularity of phrenology.[2]

The town of Fowler, Colorado is named for Fowler.[3] Fowler too had an influence on modern psychology. He is remembered as a man of universal reform who preached for education, temperance, and equality. Orson, like his sister-in-law Lydia Fowler, held forth for the equality for women at a time when women had virtually no legal rights in the United States. Orson stood for children's rights when child labor was quite acceptable in the burgeoning industrial factories of his country. Fowler as a book seller and publisher was crucial in the original publication of Walt Whitman's Leaves of Grass and other works.[4]